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When to Plant Sunflower in Rawlins County, KS

Rawlins County, Kansas Zone 6a May

Top priorities for Rawlins County, Kansas gardeners in May

We've pulled the most time-sensitive tasks for Rawlins County, Kansas this May and put them front and centre. Tackle them in order.

Avg. last frost May 1
Avg. first frost October 10
Soil temp (4") 60°F
Watering Low
Pest pressure Low
Daylight 14.2 hrs
  1. Plant out sunflower

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

  2. Plant sunflower from seed, right in the garden

    These tolerate cool soil, so you're not gambling by sowing now.

June will be here before you know it — start on
  • Starting indoors: sunflower

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Sunflowers are tall, cheerful annuals grown for their edible seeds and as pollinator magnets. They come in sizes from 2-foot dwarfs to 12-foot giants.

Rawlins County, Kansas is in USDA Zone 6a. The average last spring frost is May 1 and the first fall frost is October 10, giving you a growing season of approximately 162 days.

At an elevation of 795 feet, Rawlins County receives approximately 34.1 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Sunflower during the growing season.

Rawlins County, KS (Zone 6a) Moderate season
162 days
Last Spring Frost May 1
162 growing days
First Fall Frost October 10
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Rawlins County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (29 days to spare)
Start indoors: Feb 28 Transplant: May 9 🍅 Harvest: Jul 18 – Sep 5
Recommended (50%) ✓ Fits season (29 days to spare)
Start indoors: Mar 6 Transplant: May 15 🍅 Harvest: Jul 24 – Sep 11
Safe Start (90%) ✓ Fits season (28 days to spare)
Start indoors: Mar 18 Transplant: May 27 🍅 Harvest: Aug 5 – Sep 23

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Soil Compatibility in Rawlins County

How your county's soil matches Sunflower's growing requirements.

Soil pH

Your soil pH (6.7–7.8) overlaps with Sunflower's range (6.0–7.5), though not a perfect match.

Soil Texture

The loam soil in Rawlins County is excellent for Sunflower — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.6%). Annual compost additions will help Sunflower.

How to Plant Sunflower

1"
Planting Depth
18"
Between Plants
30"
Between Rows

Succession Planting Sunflower

2
successive plantings in your 162-day season

Sow every 8 weeks. Last sowing by Jul 02 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Sunflower

Sunflower needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Sunflower Needs Rainfall You Supplement Action
Jan 2.6" 0" ❄️ Dormant
Feb 2.2" 0" ❄️ Dormant
Mar 2.6" 0" ❄️ Dormant
Apr 3.5" 0" ❄️ Dormant
May 2.2" 4.3" 0" ✅ Rainfall sufficient
Jun 2.2" 2" 0.2" 💧 Light watering
Jul 2.2" 3.1" 0" ✅ Rainfall sufficient
Aug 2.2" 4" 0" ✅ Rainfall sufficient
Sep 2.2" 2.6" 0" ✅ Rainfall sufficient
Oct 2.2" 3.1" 0" ✅ Rainfall sufficient
Nov 2.1" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Rawlins County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Sunflower Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Sunflower needs ~1,296 GDD — county provides 2,470 GDD Excellent fit

Sunflower Planting Timeline — Rawlins County, KS

Sunflower Planting Calendar

Activity When Date Range
Start Indoors March 6 Mar 6 – Mar 20
Transplant Outdoors May 15 May 15 – May 29
Direct Sow May 8 May 8 – May 29
Harvest July 24 Jul 24 – Sep 11

Plant 1" deep · 18" apart · Rows 30" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April
May Transplant Outdoors Direct Sow
June
July Harvest
August Harvest
September Harvest
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 6a

📆 Growing Season

162 days in Rawlins County

Growing Tips for Sunflower in Rawlins County

Direct sow Sunflower outdoors after May 01 in Rawlins County when soil has warmed and frost danger has passed.

Common pests for Sunflower in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow after last frost. Stake tall varieties in windy areas. Harvest seed heads when the back turns brown and seeds are plump. Dry heads upside down.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sunflower in Rawlins County, KS?

Rawlins County is in Zone 6a with an average last frost of May 1. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is Rawlins County, KS?

Rawlins County, Kansas is in USDA Hardiness Zone 6a. The average last spring frost is May 1 and first fall frost is October 10.

🌱

Your Rawlins County Garden Planner — Free

A 24-page printable planner built for Rawlins County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Rawlins County, KS. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.